• 한국미생물·생명공학회지
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• 제23권1호
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• pp.17-23
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• 1995

We studied the influence of culture conditions on the acid tolerance of Lactobacillus casei YIT 9018 in artificial gastric juice with respect to relative amount of membrane bound ATPase and their biochemical characteristics. With raising incubation temperature from 30.5$\circ$C to 40.5$\circ$C and lengthening incubation time from exponential phase to late stationary phase, the acid tolerance of L. casei YIT 9018 was increased. As acid tolerance enhanced, C$_{18:1}$ content of membrane fatty acid was reduced and C$_{19:0 cyclo}$ was enriched but the others were not changed greatly. At high ATPase activity, proton permeability was relatively low but this phenomenon did not correspond to acid tolerance. In conclusion, it was considered that changes of C$_{18:1}$ and C$_{19:0 cyclo}$ were closely related to the acid tolerance of L. casei YIT 9018.

• Journal of Microbiology and Biotechnology
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• 제31권6호
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• pp.840-846
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• 2021

To improve the bile salt and acid tolerance of probiotics against gastrointestinal stresses, we investigated the effects of soybean lecithin and whey protein concentrate (WPC) 80 on the bile salt tolerance of Lacticaseibacillus paracasei L9 using a single-factor methodology, which was optimized using response surface methodology (RSM). The survival rate of L. paracasei L9 treated with 0.3% (w/v) bile salt for 2.5 h, and combined with soybean lecithin or WPC 80, was lower than 1%. After optimization, the survival rate of L. paracasei L9 incubated in 0.3% bile salt for 2.5 h reached 52.5% at a ratio of 0.74% soybean lecithin and 2.54% WPC 80. Moreover, this optimized method improved the survival rate of L. paracasei L9 in low pH condition and can be applied to other lactic acid bacteria (LAB) strains. Conclusively, the combination of soybean lecithin and WPC 80 significantly improved the bile salt and acid tolerance of LAB. Our study provides a novel approach for enhancing the gastrointestinal tolerance of LAB by combining food-derived components that have different properties.

• Journal of Microbiology and Biotechnology
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• 제14권5호
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• pp.1093-1098
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• 2004

An open reading frame encoding CadC, consisting of 526 amino acids, was identified from the upstream region of the Vibrio vulnificus cadBA operon. The deduced amino acid sequences of the cadC were 22 to 78% similar to those reported from other Enterobacteriaceae. Functions of cadC gene on acid tolerance were assessed by comparing acid tolerances of V. vulnificus and its isogenic mutant, whose cadC gene was inactivated by allelic exchanges. The results demonstrated that the gene product of cadC contributes to acid tolerance of V. vulnificus, and that its contribution is dependent on prior exposure of cells to moderately acidic pH. The cellular level of cadB and cadA transcripts decreased in the cadC mutant, indicating that CadC exerts its effect on acid tolerance of V. vulnificus by enhancing the expression of cadBA in a pH-dependent manner.

• Archives of Pharmacal Research
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• 제13권1호
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• pp.38-42
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• 1990

The present study was undertaken to determine the inhibitory effects of cholane compounds, unsodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA) on the development of morphine-induced tolerance and physical dependence, and also to determine the hepatic glutathione contents. UDCA and CDCA inhibited the development of morphine-induced tolerance and physical dependence significantly. UDCA inhibited the hepatic glutathione decrease induced by morphine multiple injections, while this effect was not observed in CDCA treated mice. It was throught that the inhibitory effects of hepatic glutathione decrease in morphine-treated mice by UDCA and CDCA showed a tendency of inhibitory effects of development of morphine tolerance and dependence.

• 한국식품과학회지
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• 제27권1호
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• pp.101-104
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• 1995

유제품 30여종과 야채발효 제품 2종에서 Lactobacillus casei ssp.(5 strains), Lactobacillus acidophilus(2 strains), Lactobacillus delbrueckii ssp. bulgaricus(6 strains), Lactobacillus plantarum(3 strains), Streptococcus salivarius ssp. thermophilus(11 strains), and Streptococcus faecalis(2 strains)를 각각 분리하여 이들의 내산성과 담즙산 내성을 평가하였다. 초기생균수를 고려하여 공분산분석으로 내산성을 비교한 결과, L. casei에 속하는 균주들의 내산성이 가장 우수하였으며, L. bulgaricus와 균주들은 가장 낮은 내산성을 보였다(p<0.05). 담즙산 내성은 L. casei, L. plantarum, L. acidophilus, S. feacalis 균주들의 경우 비슷한 경향을 보였으나, L. bulgaridus와 S. thermophilus 그룹에 속하는 균주들의 담즙산 내성은 거의 없는 것으로 나타났다.

• 한국미생물·생명공학회지
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• 제23권3호
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• pp.352-358
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• 1995

In this study, authors investigated the cadmium tolerance, the accumulation of cadmium, and the cellular distribution of accumlated cadmium in lactic acid bacteria under the anaerobic condition. Lactic acid bacteria grew fairly well in modified EG medium containing 10 ppm of cadmium but could hardly grow at 50 ppm of cadmium. Tolerance to cadmium of genus Lactobacillus was greater than that of genus Streptococcus, and Lactobacillus acidophilus showed the higest cadmium tolerance amomg the bacteria tested. The capacity of cadmium accumlation (9.304-12.428 mg/g wet cell) of lactic acid bacteria was higher than that (6.775 mg/g wet cell) of Escherichia coli. Lactobacillus casei of them took up the largest amount of cadmium. The cadmium elimination amount (28.46-29.25%) of lactic acid bacteria from modified EG medium containing cadmium were also higher than that (14.43%) of Escherichia coli. Accumulated cadmium in Lactobacillus acidophilus was distributed by 42.41% at cell wall, 28.97% at cytoplasm, and 28.62% at plasma membrane, respectively.

• 한국식품영양과학회지
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• 제27권3호
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• pp.433-440
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• 1998

In order to select probiotics with a high survival rate in gut and the growth inhibition of virulent pathogens to human beings or animals, we have examined a variety of microorganisms to assess the acid, bile, and pancreatic tolerance and the growth inhibition of E. colt O8 and Salmonella choleraesuis ATCC 8391. Lactobacillus acidophilus KCTC 3155 was shown to inhibit the growth of E. coli and Salmonella dramatically within 24 h of incubation, although it was vulnerable to the exposure of bile acids. Bacillus polyfermenticus showed a good growth inhibition against E. coli, with a moderate acid and bile tolerance, while Clostridium butyricum KCTC 1786 inhibited the growth of E. coli and Salmonella slightly with a good bile tolerance. However, Saccharomyces cerevisiae KCTC 7928 and Aspergillus oryzae KCTC 6075 did not inhibit the growth of E. coli and Salmonella, suggesting that these microorganisms can be used as the sources of nutritional suppliment rather than as probiotics itself.

• 치위생과학회지
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• 제1권1호
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• pp.7-11
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• 2001

Streptococcus mutans는 인간에게 치아우식증을 유발하는 주요 세균으로 구강내에서 치태(plaque)가 형성되고, 탄수화물을 분해하면서 발생되는 유기산에 의해서 생존에 위협을 받게 된다. 하지만 약산성 조건에 노출되어도 산을 경험한 S. mutans는 강산성의 조건에서도 생존할 수 있는 산 저항 및 적응능을 획득하게 된다. 이러한 산 저항능은 Salmonell enterica serovar Typhimurium, E. coli 그리고 Shigella flexneri 등에서 확인 되었던 acid tolerance response(ATR)과 유사한 기작에 의해서 얻어진 것을 알 수 있었다. 이 현상은 산성조건을 경험할 때 유도되는 protein이 주요한 역할을 하는 것을 chloramphenicol 처리에 의해서 알 수 있었다. 동시에 acid shock에 의해서 유도되는 protein 이외에 여러 가지 요소들이 복합적으로 이런 생존 능력을 갖게 하였을 것이라는 가정을 할 수 있게 되었다. 이 연구에 의해서 S. mutans의 혐기적 조건에서의 산 적응기작을 확인하였으며, 산 저항성에 관여하는 유전자의 돌연변이체를 이용한 실험이 추가적으로 필요하다. S. mutans가 구강 내에 생존하는데 필수적인 산 저항기작이 결국 치아우식증 유발의 병독소로 중요한 역할을 하기 때문에 치아우식증의 근본적인 해결을 위한 연구의 일환으로 반드시 시행되어야 할 것으로 생각된다.

• 방사선산업학회지
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• 제6권2호
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• pp.177-180
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• 2012

The acid and bile tolerance changes of 5 different lactic acid bacteria (LAB; Lactobacillus paracasei, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus plantarum, and Lactobacillus debruekii) with gamma irradiation were evaluated. The abilities of LAB to survive in the acidic conditions at the stomach and the bile acidic conditions at the beginning of the small intestine are the key functions for applying LAB to probiotics. In the results, all of LAB survived more than 50% after incubation in PBS (pH 2.5) for 2 hr, which indicated more than half of LAB are possible to pass through the stomach. However, gamma irradiation decreased the acid tolerances of LAB. The bile tolerances of all bacteria except Lactobacillus acidophilus were observed to survive at a 3% oxgall concentration in MRS, and 1 kGy of gamma irradiation to LAB did not affect any bile tolerances changes. But gamma irradiated Lactobacillus casei and Lactobacillus casei (3 kGy) showed decreasing survival rate with oxgall added MAS agar. In conclusion, gamma irradiation should be applied to yogurt or fermented foods with care because LAB could be changes their properties on acid and bile tolerances.

• 한국식품영양과학회지
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• 제26권5호
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• pp.872-877
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• 1997

Soybean curd whey(SCW) containing plenty of nutrients is the discarded by-product in soybean curd processing. To test the potential utilization of SCW as a medium for the cultivation of Lactobacilus acidophilus, the chemical composition of SCW, as well as the growth, acid production, acid-tolerance, and bile-tolerance of L. acidophilus in SCW-based media were investigated. Sucrose and stachyose, the main free sugars of SCW, were 0.42% and 0.41%, respectively. SCW contained 36.1mg/L of total free amino acids. L. acidophilus KFRI 150 showed lower cell growth and acid production in SCW than those in MRS broth. In optimized SCW-based medium supplemented with 1.0% glucose, 0.5% yeast extract, and 0.2% $K_{2}HPO_{4}$, the growth and acid production of L. acidophilus KFRI 150 increased by twice against those in SCW. In optimized SCW-based medium, the viable counts of four L. acidophilus strains were mostly at the level of $10^{9}$/ml, which is similar to those in MRS broth. Each acid-tolerance and biletolerance of four L. acidophilus strains cultured in optimized SCW-based medium and MRS broth showed no dist-inguishable difference.